温度和pH对生物成因羟基硫酸铁矿物的综合影响研究

Effects of temperature and pH on the formation of biogenic Fe(Ⅲ) hydroxysulfate precipitates

在酸性矿山废水中,氧化亚铁硫杆菌(A.ferrooxidans)氧化Fe^(2+)过程中常常伴随着次生矿物的生成.为研究温度和pH对A.ferrooxidans氧化Fe^(2+)及Fe3+水解成矿的综合影响,考察了初始pH为1.5、2.0、2.5、3.0,温度为8、18、28、38℃时体系中Fe^(2+)、总Fe、次生矿物的变化情况.结果表明,在改良9K培养基中,温度和pH均影响Fe^(2+)生物氧化和Fe^(3+)水解成矿.A.ferrooxidans最佳适宜生长环境为温度28℃,pH=2.0~3.0,其它条件均不利于其生长繁殖,导致Fe^(2+)氧化速度明显变慢.起始pH=1.5时,不同温度处理均未发现有矿物生成,pH越高,收集矿物量越多.次生铁矿物XRD图谱表明,反应温度为28℃时,pH=2.0~2.5条件下次生铁矿物主要为黄铁矾和施氏矿物的混合物,而pH=3.0时则更有利于施氏矿物的形成.该现象对有效调控次生矿物的形成具有潜在意义.

To illustrate the effect of temperature and pH on the biooxidation of Fe^（2＋）and the formation of secondary iron minerals,Fe^（2＋）,total iron,and newly-formed mineral phase were observed at the different initial pH values of 1. 5,2. 0,2. 5,3. 0,and different temperature of 8,18,28 and 38 ℃. The results show that A.ferrooxidans oxidized Fe^（2＋）fast at the optimal condition of 28 ℃ and pH 2.0 ~ 3.0. The oxidation rate of Fe^（2＋）was significantly slower under other conditions.Furthermore,initial pH would affect the mass and phase of biogenic secondary iron mineral. The higher of initial pH,the more mineral amount collected.The XRD patterns show that the formed iron mineral was a mixture of jarosite and schwertmannite at 28 ℃ and pH 2.0 ~ 2.5,but the initial pH 3.0 were more conducive to the formation of schwertmannite. This phenomenon has potential implications for the effective regulation of the formation of secondary minerals.